Leaf Custom Gain Adjuster

[roskav]

I said I'd post a screen grab of work in progress for David Anderson who started this thread, but under another sub-forum.. here you are ... just some dull shots this morning .. but you can see how the 35mm has a particular cast that has been removed from the adjusted file... I parcel everything out to different folders as per Yair but I throw everything back together so I can judge the success of the proccess.... no fall off correction applied as I want to keep the sky as dark as I can.... (Still using LC 10 on the desktops but 11 is working great on the laptop.... just haven't had the time to load up)

Ros

[M_M]

Hello,

This maybe a very silly question, but what do Leaf and Sinar owners do when shooting an exterior dusk photo and your exposure is in the range of 20 seconds?
If I’m not mistaken, both Leaf and Sinar can go as long as 30 seconds only. Since you cannot change your F stop and your back does not allow you to increase you time exposure beyond 30 seconds, I guess the only way to do it is to carry a portable strobe with you. Is this correct? If so, is it not important that your gain photo is exposed for a fraction of a second only? What I’m trying to find out is if the lack of noise in the gain file compared to the actual shot exposed at 20 seconds makes any difference.

Now for Phase users; is your 80 second exposure the same in terms of noise as the 20 second exposure? Do you simply increase your time exposure and use this file to correct the cast?

I’m in the process of selecting a back and it has been very frustrating so far. Thanks for your help.

Mariusz

[Streetwise]

I said I'd post a screen grab of work in progress for David Anderson who started this thread, but under another sub-forum.. here you are ...
Ros
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Thanks Ros, that's very helpful indeed! Are you shooting tethered with V10 and using the custom gain adjuster as you go? (Maybe you already said so - I apologize)


Mariusz - Wow, those certainly are long exposures! I had always heard that the Sinar 54H was the best back on the market for long exposures, but I don't care for their software at all. I own a Leaf Aptus, but I've never had it up past two seconds. I always assumed that the noise would be too much... Maybe someone will chime in on that... I can't speak to Phase results.

Dave

[mtomalty]

but what do Leaf and Sinar owners do when shooting an exterior dusk photo and your exposure is in the range of 20 seconds?

Mariusz

I'll preface my response by saying that I don't own a DB but I regularly use the current
products from Leaf,Hasselblad,and Phase on a regular basis.


I did a recent shoot that had pretty well the parameters you outlined above.

I was shooting with an Aptus22 well after sunset and my exposure time was in the vicinity
of 20 seconds.  In this situation,knowing that i would not be able to expose the neccessary
Gain adjustment file I used an alternate gain file that i had exposed a little bit earlier in the
evening shooting the same scene with the same exposure/movement details as I knew i
would be requiring a little later.

Worked to my complete satisfaction except that there was some dust differences on the
sensor between the two exposures which the gain file tried to remove from the image
where there was none resulting in a couple of funky little spots that took a few seconds in
post to take care of.

Hope this helps a bit.

Mark

[M_M]

Dave - thanks for the info. I think you are correct, the 54H might be a great back, but unfortunately it does not have a screen and therefore it would not work for me.



Mark – thanks. I’m glad to hear that you can use a shot taken much earlier. It would seem that color temperature of the Gain file does not have to match the color temp of the shot that needs to be corrected. However, not always do you have a luxury of doing what you were able to do, so I guess I would love to hear from someone if a small portable strobe is the only way to go (in the field) and if the lack of noise in the gain file created this way may cause problems?
Mark, do you remember how long your gain exposure was? Was it a short or was it a few seconds? You may have the answer to my noise question.

Thanks again.

Mariusz

[yaya]

Mariusz,

The gain file can be captured anywhere, anytime with a strobe, with the sun or whatever. It needs to be exposed properly and must be taken with the same aperture and movement as the actual shot.
The movement parameters I sometimes write into the metadata on the back for reference.

Yair

[M_M]

Thanks Yair.

Mariusz

[mtomalty]

Mariusz

In the example I referenced I had done a series of gain files (15-20 minutes earlier than
final capture) that ranged anywhere from 5 to 20 seconds.
I randomly selected one and applied it to my selected final file and,for all intents and
purposes,arrived at a 'perfect' final corrected.

I'm far from knowledgeable enough to determine whether or not the different time exposure
or white balance contributed any measureable negative issues but I do know that the
'gained' file was completely satisfactory for my needs.

As a landscape photog I have also done a number of 5-10 second exposures of waterfalls,etc
using a Hassedlblad ArcBody whose optics definitely require gain correction and could determine
no adverse effects applying 20-30 second gain correction files to my originals.

Yair could more definitively state whether such differences could introduce noise issues but
in my experience,I have seen none.

Mark

[M_M]

Mark - thanks a lot, this helps quite a bit.

Mariusz

[Prakash Patel]

Dave hi,

V8 allows you to create a custom gain file that can be loaded into the back when tethered to either V8 or LC11. It sits under Camera>Calibration>Gain. You can store a library of these files and load them as required, so as you shoot the images come up corrected for casts and falloff.
A simplified version of this process is going to be implemented into LC11 in the near future.

Yair
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Is Leaf going to continue to support V8?
I will confess that I do not use the full capability of what is possible in this software much less understand all the customized/advanced possibilities. The one thing that I believe is unique is the modular GUI of all the tool pallettes and controls when shooting in a tethered mode. The ability to
control and see all tool pallettes simultaneously  without having to navigate through pull down tabs is  efficient and comfortable when shooting tethered. Historically software manufacturers
typically abandon or stop supporting  previous versions............some times new is not better it is just different. Don't get me wrong, I use V11 and it is an improvement  from V10 especially for post production.

The other feature is this 8 shot gain file. I was under the impression this was originally designed to address optical imperfections of the glass filter in front of the CCD for studio product shooters.
In concept, for tethered shooting this works great for removing digital optical anamolies(color casts, vignetting,dust,centerfolds)
In practice, as pixjohn has mentioned, the amount of time it takes to gather the data from 8 shots
is particularly uncomfortable when a client or art director is present.
 Yair, can you elaborate why Leaf doesn't make a "simplified version" for V8..............a oneshot gain file that can be uploaded to the back? Particularly since you have mentioned that the custom gain file created in V8 can be used in V11.

thanks

[pixjohn]

Prakash, you forgot to mention the one problem with magenta highlights we both have using the V8 gain file and 24xl lens. I still have the problem and still do not have a fix. Here I am supporting this great program with no fix for my own use. Please Leaf help us out.

Gain File Problem

[Streetwise]

It takes a few step but I just shoot the Gain in V8 and upload the file to the back. I then shoot my images in V10. I am going to try V11.2 since it now works with V8. I just use a simple $35 mini strobe screwed into a socket pointed directly at the lens approximately 15 inchs away.
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Can you have both versions open at the same time and go back/forth? I used to crash when I tried having V8 and LC10 open at the same time...

Secondly, do you ever get into stitching images together? If so, do you create a custom gain for each lens movement for the shot (ie. +5 H shift right, and -5 H shift left) or just one custom gain for the lens set at 0 movements?  I might have asked this earlier, but can't find it.

Last of all, do you have any experience with using the "merge to HDR" functionality in Photoshop, where you might take a series of 6 bracketed exposures into photoshop in an effort to retain your highlight and shadow detail? If so, it seems like shooting V8 gains to the back, and bracketed shots in LC11.2 would be the *only* way you could work most efficiently.

Dave

[pixjohn]

I have both versions open at the same when I am shooting. However you can not  have both softwares open and connect the cord, the computer will crash.

Can you have both versions open at the same time and go back/forth? I used to crash when I tried having V8 and LC10 open at the same time...

Secondly, do you ever get into stitching images together? If so, do you create a custom gain for each lens movement for the shot (ie. +5 H shift right, and -5 H shift left) or just one custom gain for the lens set at 0 movements?  I might have asked this earlier, but can't find it.

Last of all, do you have any experience with using the "merge to HDR" functionality in Photoshop, where you might take a series of 6 bracketed exposures into photoshop in an effort to retain your highlight and shadow detail? If so, it seems like shooting V8 gains to the back, and bracketed shots in LC11.2 would be the *only* way you could work most efficiently.

Dave
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[Streetwise]

I have both versions open at the same when I am shooting. However you can not  have both softwares open and connect the cord, the computer will crash.
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I'm not sure I follow you. Don't you shoot tethered? Your statements seem to contradict. Sorry if I'm kind of dumb... Maybe you're saying that you open V8, connect, and then open LC10? I guess that would make sense. Then you disconnect, shut down V8, connect to LC10, and open V8 back up to do your final shots?


Dave